Powder was 63.5 gr of H1000 and brass was once-fired Weatherby (Norma).

I think the only variables were the new scope, new rings and Barnes bullets.

I sighted in using some year-old reloads made up of the same brass and 117 gr Sierra GameKing bullets (63 gr of H4831). Adjustments to the scope were exactly as expected (4 clicks = 1 inch in any direction at 100 yds). Finally, I shot two 3-short groups with the Sierras at 50 yards (point of impact .5" high)

Then I moved to the Barnes at 100 yards.

The first bullet missed the target entirely. I shifted back to 50 yards and more or less hit the bullseye. Back to 100 yards - another miss. I'm scratching my head in dismay.

Finally, I came back to 50 yards and shot 6 of the Barnes and got a spread from 4" at 7:30 to 2" at 10:30. Clearly, the shot at 7:30 would have missed the 100 yard target.

There was a guy shooting next to me who was a gunsmith and he very kindly took a look at the gun/scope. He could find nothing wrong. He suggested that since the Barnes are sold copper, maybe they have to make them slightly smaller (sold copper not being able to "squeeze" down a barrel as easily as a lead-based bullet).

I just miked the two bullets (Barnes and Sierra). The difference is not measurable by my non-digital mike and tired eyes but after setting the mike on the Sierra, the Barnes IS slightly smaller. Not enough for me to mike the difference but enough to feel a wiggle.

If you put a precision mic on the different bands and body segments of Barnes' solid copper bullets, you'll find that most are tapered or wasp-wasted (depending on the design).
I'd like to say it's so the bullets can handle the various bore dimensions seen in factory rifles, without causing excessive pressure in the tighter bores. .....but I don't really know if it's intentional, or just a byproduct (mild defect) of their manufacturing process.

__________________"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."

It pretty well must have, since that what you were getting. What other explanation is there?

It shouldn't take any more time than any other load work up. Shoot your rounds. They'll either stabilize as you approach max or they won't. If they don't, you have an inaccurate load. If they do and you're happy with the accuracy, you're golden.
Should be just like any other load work up.

Absolutely. If you are getting keyholes, the bullets are tumbling end over end in flight. Did you ever shoot pennies out of a slingshot? They curve all over the place. Similar effect when you have a tumbling bullet. I had some 45 Colt loads that were tumbling on me earlier this year. At 30 yds, I had bullets hitting 10 feet from each other. One bullet hit five feet to the right of my target, then another one hit a good five feet to the left. So when they are tumbling, there's no telling where they will go.

In my case, I tried a different powder and the problem went away. The tumblers shot perfectly fine out of a different gun however. It may not fix your problem, but it may not hurt to try a different powder.

My .25-06 (Tikka T3) is a 1:10 as well. The 115 Barnes FBs are the most accurate bullet I've loaded. Sub MOA @ 100 yds. I can't imagine the 06 Remington can stabilize it but the weatherby can't. Maybe try H4831. That's what I use.

Here's picture of the target. I initially thought there was only 1 keyhole but clearly all but maybe 2 are keyholed. My powder charge was at the suggested starting amount but the max is only 4 grains higher. Would such a small increase turn around this unbelievable effect?

My .25-06 (Tikka T3) is a 1:10 as well. The 115 Barnes FBs are the most accurate bullet I've loaded. Sub MOA @ 100 yds. I can't imagine the 06 Remington can stabilize it but the weatherby can't. Maybe try H4831. That's what I use.

I know a lot of people have great success with this bullet which is why I'm so surprised. H4831 and H1000 are both slow-burning powders and somewhat similar.

If increasing the velocity is the answer, then what will happen to the bullet downrange when the velocity reduces? Will it start out stable and keyhole at longer distances?

I am so tempted to abandon it altogether and go back to my GameKings or maybe try Nosler BTs...

My guess is your particular problem is because lead free bullets are longer for their weight. They may be 115gr, but their length will be longer than a "normal" 115gr bullet, and contrary to what many think, its length, not weight which determines if a bullet will stabilize with a given twist rate.

I bet the 100gr TSX would shoot much better, as its length is more in line with what a 115gr conventional bullet would be....

It's interesting that the Barnes TSX bullets of different weights have almost the same BC. Every other bullet I've checked has a larger BC for increasing bullet weight.

The Nosler Ballistic Tip seems to have a better BC than the Partition; almost as good as the Berger...

I don't think Bergers would work will with my gun (if it has "huge freebore") as Berger recommends lengthening a round to where the bullet almost touches the lands. That would be hard to do in my case.

It's interesting that Sierra gives different BC values for different velocities; slower is not better

In your photo, I don't see anything truly key-holing, but they may be yawing (still a stability issue).

Don't worry about the ballistic coefficients. They have far more to do with a bullet's flight characteristics, than stability. And, a bullet's shape affects the BC more than length alone.

Unrelated to the OP, but related to your last post....
Note how Sierra quotes multiple BCs for their bullets.
That's because G1 ballistic coefficients actually change significantly in flight (as velocity changes). And, the standard G1 model doesn't apply well to modern boat tail designs.

Because of this, manufacturers have to decide what BC to use. Some use the highest BC the bullet is likely to achieve. And, some are more conservative and use an average of the expected velocities to get their BC.
Without knowing what velocity is used to calculate the listed BC from any given company, comparing G1 BCs of different bullets really doesn't do much good unless they're significantly different (like a .273 vs a .426).

Most precision bullet makers will also list the G7 BCs for their bullets. The G7 model is much better suited to modern boat tail bullet designs, and allows for more precise ballistics calculations. But... G7 BCs are much lower for any given bullet, than the same bullet's G1 BC. So, "main stream" manufacturers are hesitant to start listing G7 BCs for their bullets. They don't want people getting confused and thinking the lower G7 BC is representative of the older standard of the G1 BCs.
Here's an article, if you want more information. (It also has representations of the G1 and G7 standard projectiles.)

__________________"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."

Don't worry about the ballistic coefficients. They have far more to do with a bullet's flight characteristics, than stability.

Sorry to belabor this, but if bullet stability is not a function of BC, what is it a function of? Is there some minimum muzzle velocity for any given bullet and barrel length/twist? Are we "doomed" to learn about each bullet's stability with each gun by trial and error; hopefully not...

Thanks for the useful presentation of BC data. I knew Berger gave G7-BCs but I've not been able to make comparative use of it (other than between Berger bullets) as no other bullet manufacturers give the same data.

Ballistic Coefficients are a numerical representation of how closely a projectile's in-flight performance conforms to that of the "standard projectile". So, as mentioned earlier, that's generally the G1 standard projectile.

A Ballistic Coefficient represent a bullet's resistance to aerodynamic drag.
Having an approximation of that factor allows one to calculate fairly precise trajectories for a given velocity.

That's pretty much it. BCs just tell you how well the bullet will resist aerodynamic drag, in relation to the "standard projectile".

When we're talking about stability, we're referring to rotational stability: A bullet rotating in a manner that is stable and predictable, around its long axis.
A rotational velocity that is too low may not keep the bullet stable on that axis; and a rotational velocity that is too high can magnify small balance imperfections in the bullet, causing it to also be unstable.
(If you rotate them really fast (like 350,000 rpm), they can self-destruct before they reach the target.)

By saying your rifle is not stabilizing the Barnes 115 gr TSX, we're referring to them having a low rotational velocity. They just aren't spinning fast enough to remain stable in flight. To fix that, you must increase velocity, or the barrel twist rate. Since replacing your barrel probably isn't on your to-do list, increasing the powder charge for more velocity is the better solution (if you can do so).

If you can't find a powder that will get you enough velocity to stabilize that bullet in your rifle, you have two choices: 1. Forget about that bullet. 2. Rebarrel the rifle with a faster twist rate.
(I would opt for #1.)

If I was in your position, I would:
Give away the rest of the bullets, if it was a box of 50.
Increase the load, to try to make these work, if you bought 100 or more.
And use the 80 gr TTSX (or 100 gr TSX - the heaviest I would go) if you want to try a different Barnes bullet.

__________________"Such is the strange way that man works -- first he virtually destroys a species and then does everything in his power to restore it."

I took the following from the Barnes website for this bullet and H1000: Starting Load 63.5 (3101) and Max Load 67.5 (3243). That's quite different from 66/72. I would think boosting the load from 63.5 to 72 (13%) might give enough of a velocity increase to stabilize the bullet. nmbrinkman says his Tikka T3 does very well with this bullet using H4831. He doesn't say what his load is (min or max) but I believe H1000 has about the same burn rate as H4831.

It's pretty clear now that this bullet needs more "umph" for my barrel. I would never have thought that different barrels for the same caliber would have different "umph" requirements but I guess they do.

I think, as in the old closing of Dragnet, "This case (on this bullet in my barrel) is closed"!

I just wish we could establish some direction as to which bullet shape might be most likely to be better stabilized in my barrel without needing max loads.

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